Process of making black polyazo dyes.



NITED STATES ATENT OFFICE.

JENS DEDICHEN, OF BERLIN, GERMANY, ASSIGNOR T0 AOTIEN GESELL- SCHAFT FI TR ANILIN FABRICATION, OF BERLIN, GERMANY.

"PROCESS OF MAKING BLACK POLYAZO 'DYES.

SPECIFICATION forming part of Letters Patent N 0. 717,550, dated January 6, 1903.

Application filed June 13, 1902. Serial No. 111,468. (170 specimens.)

To all whom, it may concern:

Be it known that I, J ENS DEDICHEN, of Berlin, in the Kingdom of Prussia, German Empire, have invented new and useful Improvement-sin Processes of Making Black Polyazo Dyestufis; and I do hereby declare that the following is a full, clear, and exact description thereof, which will enable others skilled in the art to which it 'appertains to make and use the same.

In the German Patent No. 97,437 there is described the manufacture of polyazo dyestuiifs represented by the formula.

in which P means a paradiamin, and R the radical, of a diazo compound. These dyestuffs are produced by allowing a diazo compound to react with a mixed disazo dyestufl, such as may be obtained by combining either in an alkaline solution or in a solution rendered acid by means of acetic acid a tetrazotized paradiamin with one molecular proportion of 1.8-amidonaphthol-3.(i-disulfonic acid and combining thereupon the intermediate product thus formed in an alkaline solution with metaphenylenediamin or witha homologous diamin.

It is known that when following the directions given in the above patent the reaction is performed, so as to make the radical of the diazo compound enter into. the benzene nucleus of the Inetadiamin, while the naphthalene nucleus of the amidonaphthol-disulfonic acid remains intact. There is no doubt of this disposition being caused by the factthat the formation of the intermediate product above referred to takes place in an alkaline solution or yet in a solution free from mineral acid.

I have now made the unexpected discovery that coloring matters absolutely different from the products described in the German Patent No. 97,437 are obtained if diazo compounds are allowed to combine with mixed disazo dyestufis, the intermediate products of which had been formed in the presence of mineral acid. It seems that under these conditions the diazo compound instead of entering into the benzene nucleus reacts with the the following example.

naphthalene nucleus, occasioning thus the formation of new coloring-matters. If, for instance, diazobenzene is allowed to react with the mixed disazo dyestuft derived from benzidin-l. 8 amidonaphthol-3. 6 disulfonic acid and metaphenylenediamina dark violet dyestuif will be obtained when following the directions given in the German Patent N 0. 97,437 to the formation of the intermediate product, while theisomeric product obtained according to the prescriptions of the present demand forms a greenish-black dyestuff.

To further illustrate my invention, I give The parts are by weight: 18.4 parts of benzidin are tetrazotized in the usual way by means of fourteen parts of sodium nitrite and ninety parts of hydrochloric acid, (specific gravity 12 Baum.) To the solution obtained is then slowly run an aqueous solution of the neutral sodium salt of 1.8-amidonaphthol-3.6- disulfonic acid, prepared by dissolving thirtytwo parts of the said acid in water on addition of the theoretical amount of sodium carbonate. The mixture is then stirred until the combination is complete, the intermediate product separating in the form of a black precipitate. 'A solution containing 10.8 parts of metaphenylenediamin is then added thereto, and the mass is rendered alkaline by the addition of forty-five parts of calcined sodium carbonate. Stirring is continued for some hours more and a diazo solution obtained by diazotizing in the well-known way eleven parts of anilin by means of eight and one half parts of sodium nitrite, and sixteen parts of hydrochloric acid is added thereto. After stirring for some hours more the mass is heated up and the polyazo dyestufi is precipitated by means of common salt. on unmordanted cotton from a bath containing soap or common salt greenish black shades of great intensity.

It produces in What manner the same is to be performed, from a paradiamin with 1.8-an1idonaphth0l- What I claim as new is- 3.6-disulfonic acid and combining the inter- The process for the manufacture of black mediate product thus formed in an alkaline polyazo dyestuffs, said process consisting in solution with a metadiamin. 5 allowingadiazo compound to react onanlixed In witness whereof I have hereunto signed disazo dyestuff represented by the formula: my name, this 28th day of May, 1902, in the 1.8-amidonaphthol-3.6-disulfonic acid Presence of two Subscribing Witnesses- JENS DEDIOHEN. metacllamln 1..

W 1th esses: 10 obtained by combining in the presence of free HENRY HASPER,

mineral acid the tretrazo compound derived WOLDEMAR HAUPT. 

